obscure

(adj.) - If something is obscure, it is cloudy or dark, difficult to understand, or not very well-known.
*This word can also be used as a verb.

• Word Family: obscurity
• Synonyms: hazy, cloudy, unclear, vague
• Antonyms: clear, vivid, obvious, understandable
• Origin: 1400 Latin, from ob "over" + -scurus "covered," which comes from the ancient European root skeu- meaning "to cover or hide"
• Example: No matter how much scientists have discovered, the true cause and effects of a black hole are still obscure.

The word camera comes from the Greek word kamara which means "vaulted chamber."
Early astronomers like Galileo used the concept of camera obscura to study space. What could that mean?